Ball mill



July 6 1926..

P. T. LINDHARD BALL MILL Filed August 15, 192s 2 Sheets-Sheet 1 Lip/@wk July 6,1926'. A

Y P. 'l'. LIINDHARD BALL MILL Filed August 15, 1925 2 Sheets-Sheet 2 Patented July 6, 1926.

UNITED 'STATES rovL m. LrNDHann', or BROOKLYN NEW Yoan, assrcnon To F. L. sMrD'rrr a' co., or NEW YORK, N. Y., A conronrirroN or NEW JERSEY.

BALL MILL.

Application filed August 15, 1925'.v Serial o. 50,353.

ing compartment, the tailings iointl'ie sepa-V rating"compartment being' continuously retua-ined tothe preliminary grindingcomparb ment for regrifnding and the material which' passes'th-ron r the separator being delivered to the secondary grindi-i'ig' compartment. The object o ii the invention is to' improve' suoli miills in various structural features JEoithe purpose oi'increasing eiiiciency, facilitating the'rasseinh-ling of parte and theA substitution of screens of different mesh airdsize according to the nature of the materials operated' upon, reducing' wear Yoirnuts which must he reniovedf'in such: suhst'itution, reducing costieri"manufacture, and generally improving construction. In the improved mill the screen fin the'l separating compartment is suhstantially cylindrical 'andi concentric with the shell: ofthe mill; the material from the preliminary grinding Compartiment passes upon the screen at' one end, the lines' pass' throughy the screen and arecarriedon 4.to the seconda-ry grinding' compartment, andi the tailings pass from the screen at the `further endandafretlien" returned to the preliminary grindingl compartment'. The full area ofthe screen`l thus l'iecoines effective', andi is notf limited by 'thearrangement ofthe means for returning the ,tailings orv for passing on the fines.. The" construct-ion isl suchmoreover,

tliatthe screens can Aloe vremoved from the' outside' of the inillf'Y readily andl other'screens* substituted aslmay'be desired. Various die"- tails o'l construction Willi liemore` fully'par# ti'cularly'referred'to hereinafterv with` lreference tothe' accompanying drawings in which the iirventionis' illustrated. as embodied in a convenient and practical form' andV in Wliicl'r:

Figure l is a' partial longitudinal section ofiagmillof the character4 referred to, showin'gra' portion-ofthe' preliminary grinding' compartment, the separating compartment, andthe adjacent Aportion of' the secondary grinding compartment.

Figures' 2" and" 8l are views in transverse section on the' planes indicated by. tl'iebroken lines 2--2 and 343", respectively, of Figureil.

Tlie'shella of theniilly may be constructedlA as usual andis shown ascontinuousv and asr provided in the' preliminary-griirding con-ipartment A 'with liners b, and ini the; secondary grinding coi'iipartment C with* liners'l c. In the' separating compartment vthe s'hel'l is shown ecs-having a liner ci', The preliminary' grindi-'iig compartment ifs sho'vvn as havin-g" a single maiihole provided With'a cover E, While the Ysecoiidary grinding compartment C, is shown also Vas havi'i'ifg single -nianhole' provided with cover F. A The separating coinparti-i'ient, however, is shown as having several manholes or hand-holes, to facilitate the renioval aiid repl'acen'ient'of the screens, each manhole or handhole having a coV'erG, which'is supported hy and secured' toa suitable traine D, whiclr is ina-de siiificiently heavy tov coinp'en'satef for the,possiblel Weak# eni'ng of thev 'sliell hy the several Vmanholes or lian'dholes. AerllY of the detail's'of coifistru'cL tion thus tar referred to maybe of any usual or suitable'character.

Securedto the sliel-llawvithin the same at a suitable point' is-an angle ifi-oir ring gftlov the' inWai-dly projecting'ilai'ige otwliichl is secured,A as hereinafter described?, an aiiini'rlar' plate c which ini VturnE has secured thereto" theV outer ends of the several perforated or slot'ted'pl'atfes j', througl'i which theiines 'frinf` the preliminary grinding compartment" pass'v cured* tof the annular plate c', isan?l angle'y iron ring' g, the plates f and' the ring@t t'iein'gconveniently 'seci'i'redtoy the" annular" facilitate -the renjiovali and? replacement of the screen through tfl-ieli'andholes g.' its other end:v the cylindrical screen? 'issupportedi onfthe periphery of' a-"plate g" to befrei'erred to. l

At the other side of5 thespace Set -Yap'a'r-t for the separating con'i-paitnient tlierei secu'red to the inside of' the shell? dg" an" angle iron ring Z5, to?. the verticalE flange" o'fv'hich is secured an annular plate L which extends well toward the axis of the shell. Liners m are preferably secured, as by bolts n, to the face of the.plate 7c toward the secondary grinding compartment C, the heads of the bolts being countersunk in the liners and the nuts being on the other face ot the plate where they are readily accessible and less exposed to wear. The inner ends of the liners m, may also be received within an undercut ring 0 held by bolts o.

To the plate c, on its face next the separating compartment, are secured channels p, by which the fines which have passed from the intermediate portion ot the separating compartment through the screen y', and into the annular space between the same and the shell a, are conducted toward the secondary grinding compartment c, while the tailings, rejected by the screen j, are conducted by channels r, provided with flights s, and secured to the separating side of the plate g, above mentioned, toward the central conveying tube w.

Centrally in the mill is disposed a double deliecting cone t, with radial ribs u and '0, by which the fines received from the channels p, are directed into the secondary grinding compartment C, and the tailings received from the channels r, are directed into the conveyor tube by which they are returned to the preliminary grinding compartment A. In the construction shown the conveyor tube is conical, made up of several sections fw, lw', and and is provided interiorly with flights a, by which the return of the tailings to the preliminary grinding compartment A is eected. In the construction shown bolts 0, above mentioned, with nuts exposed in the separating compartment, serve to secure together the liners m, the plate k, the ring o, the channels p and r, the double deiecting cone t, and the section 'w ot' the conveyor tube, while the sections w and a: of the conveyor tube receive between them the inner ends of the perforated or slotted plates f, and are secured together by bolts y, and also have their nuts within the separating compartment. The section m, of the conveyor tube forms an extension with the preliminary grinding compartment by means of which the tailings are carried somewhat within the preliminary grinding compartment so that they are subjected to a further grinding action before they are again presented to the plates f.

The movement of the fines in the annular space between the screen y' and the shell a, toward the channels p and the secondary grinding compartment C, is facilitated by flights g, on the inner faces of the handhole covers G, so that such flights are removed with the covers and do not form an obstruction to the introduction of the screen, the shell a and its liner a', within the separating compartment, being lett without flights between the handholes.

It will be understood that various changes in details of construction and arrangement can be made to suit diiterent conditions of use without departing from the spirit of the invention.

I claim as my invention:

l. In a ball mill, the combination of a shell, partitions forming a preliminary grinding compartment, a separating compartment and a secondary compartment, the partition between the preliniinary grinding compartment and the separating compartment being perforated, a substantially cylindrical screen in the separating compartment and concentric with the shell, means to direct the lines 'from one end of the screen to the secondary grinding compartment, means to return the tailings from the screen to the preliminary grinding compartment, the shell having a handhole for com` munication with the separating compartment, a cover for the handhole, and conveyor flights on the inner face ot the cover to promote movement of the lines toward the secondary grinding compartment.

2. In a ball mill, the combination of a shell, partitions forming a preliminary grinding compartment, a separating compartment and a secondary grinding compartment, the partition between the preliminary grinding compartment and the separating compartment being perforated in its intermediate portion, a substantially cylindrical screen supported between the partitions concentric with the shell and forming an annular space between itself and the shell, means to direct the iines from said annular space to the secondary grinding compartment, and means to direct the tailings to the preliminary grinding compartment.

3. In a ball mill, the combination of u. shell, partitions forming a preliminary grinding compartment, a separating compartment and a secondary grinding comartment, the partition between the preliminary `grinding compartment and separating compartment being perforated, a substantially cylindrical screen supported between the partitions concentric with the shell, a double cone deilector mounted centrally with respect to the partition between the separating compartment and the secondary grinding compartment, channels to direct the fines from one side of the screen to one side of said deiiector, channels to direct the tailings from the other side of the screen to the other side of said deflector, and a conveyor to conduct the tailings to the preliminary grinding compartment- 4f. In aball mill the combination of a shell, an angle iron ring secured to the inside of the shell, an annular plate secured to the fi l) lll) vertical flange of said ring, and perforated plates, forming a partition, secured lto said annular plate.

5. In a ball mill, the, combination of a shell, an angle iron ring secured to the inside of the shell, an'annular plate secured to the Vertical flange of said ring, a substantially cylindrical screen supported at one end on the horizontal flange of said ring, and means to support the other end of said cylindrical screen.

6. In a ball mill, the combination of a shell, an angle iron ring secured to the inside of the shell, an annular plate'secured to the Vertical flangev of said ring, perforated plates forming a partition secured to said annular plate, a substantially cylindrical screen supported at one end by the horizontal flange of said ring, and means to sup- Y partment, a. third annular plate between said channels and the separating compartment, and other channels to direct the tailings to- Ward the preliminary grinding compartment. Y

8. In a ball mill, the combination of a shell, a perforated partition, an angle iron ring secured to the inside of the shell, a plate 4 secured to the Vertical flange of said ring and extending'well toward the axis of the shell and forming a partition, said partitions forming aV preliminary grinding compartment, a separatingcompartment and a secondary grinding compartment, a substantially cylindrical screen between the two partitions, channels supported by said plate to direct the fines toward the secondary compartment, a third annular plate between said channels and the separating compartment, and a double cone deflector to deflect the fines from the first mentioned channels to the secondary grinding compartment and to direct the tailings from the second named channels toward the preliminary grinding compartment.

9. In a ball-mill, the combination of a shell, a perforated partition, an angle iron ring secured to the inside of the shell, a plate secured to the Vertical flange of said ring and extending well toward-the axis of the shell and forming a partition, said partitions forminga preliminary grinding compartment, a separating compartment and a secondary grinding compartment, a substantially cylindrical screen between the two partitions, channels supported by said plate to direct the lines toward the secondary compartment, a third annular plate between said channels and the separating compartment, and a central conveyor tube to conduct the tailings into the preliminary Vgrinding compartment This specification signed this 12th dayof August A. D. 1925.

POVL T. LINDHARD. 

